Red wine is produced by first crushing red and black grapes and then fermenting the crushed grapes including their skins, seeds, grape juice and pulp (also called must).
Usually, yeast is added to the must to start the fermentation process. Fermentation may also occur naturally. During fermentation, the yeast converts the sugars in the grape juice into ethanol and carbon dioxide. The rising carbon dioxide pushes the grape skins to the top and forms a “cap” or “head” of grape skins on the surface of the fermenting red wine. The cap includes naturally occurring substances that are useful in the fermentation process and the overall quality and taste of the wine. Therefore, the free-run wine is pumped and sprinkled over the cap in order to extract and mix the naturally occurring useful chemicals with the free-run wine in the bottom of the fermentation tank.
Several devices have been used to facilitate the pumping and sprinkling of the free-run wine over the cap. Homogeneous distribution of the free-run wine over the cap is critical to the quality and taste of the wine. Also critical are the unobstructed flow of the free-run wine through the wine-pump over and sprinkling device, the droplet size of the wine exiting the sprinkling device and the ease of cleaning of the device.